FAQ on how to include all org files in a directory is incorrect (view 85).
Correct code is:
(setq org-agenda-files (file-expand-wildcards "~/org-files/*.org"))

You are right.
This isn't valid: (setq org-agenda-files "~/my/special/path/org/")
M-x org-agenda RET will reply with: `org-agenda-files' cannot be a single
directory
I propose the following for the FAQ:
(setq org-agenda-directory "~/Org/")
(setq org-agenda-files (directory-files (expand-file-name org-agenda-directory) t
"^[^\.][^#][[:alnum:]]+\.org$"))
That will add every org file. I've had the problem of normal glob
expansion to include emacs lock files that are in this format:
.#todo.org
I was under the impression that org-agenda-directory set to
~/my/special/path/org/ would Just Work(tm) because if you do C-c a a v A
it pulls in the right files for me.